1. Field of the Invention
The present invention relates generally methods for forming chlorine containing plasma etched patterned layers within microelectronics fabrications. More particularly, the present invention relates to hard masking methods for forming chlorine containing plasma etched patterned layers within microelectronics fabrications.
2. Description of the Related Art
Microelectronics fabrications are formed from microelectronics substrates over which are formed patterned microelectronics conductor layers which are separated by microelectronics dielectric layers.
As microelectronics fabrication integration levels have increased and microelectronics fabrication device and patterned conductor layer linewidth dimensions have decreased, it has become increasingly challenging to form within microelectronics fabrications chlorine containing plasma etched patterned layers, such as but not limited to chlorine containing plasma etched patterned conductor layers (including but not limited to patterned metal conductor layers, patterned metal alloy conductor layers and patterned metal silicide conductor layers) and chlorine containing plasma etched patterned silicon layers (including but not limited to patterned amorphous silicon layers, patterned monocrystalline silicon layers and patterned polycrystalline silicon layers), with a uniform and attenuated linewidth. The challenge of forming chlorine containing plasma etched patterned layers with uniform and attenuated linewidth within advanced microelectronics fabrications typically derives from: (1) a reduced depth of focus with which an advanced photoexposure apparatus may photoexpose a blanket photoresist layer to form within a microelectronics fabrication a patterned photoresist etch mask layer of attenuated linewidth, thus limiting the thickness of the patterned photoresist etch mask layer of attenuated linewidth so formed; and (2) a corrosive and/or erosive effect of a chlorine containing etch plasma upon the patterned photoresist etch mask layer, when the patterned photoresist etch mask layer is employed for defining a chlorine containing plasma etched patterned layer from a chlorine containing plasma etchable blanket layer formed beneath the patterned photoresist etch mask layer, while employing the chlorine containing etch plasma.
It is thus towards the goal of forming within microelectronics fabrications from chlorine containing plasma etchable blanket layers chlorine containing plasma etched patterned layers of uniform and attenuated linewidth while employing chlorine containing plasma etch methods which in turn employ patterned photoresist etch mask layers of attenuated linewidth and attenuated thickness that the present invention is directed.
Various chlorine containing plasma etch methods have been disclosed in the art of microelectronics fabrication for forming from chlorine containing plasma etchable blanket layers chlorine containing plasma etched patterned layers within microelectronics fabrications.
For example, Abernathey et al., in U.S. Pat. No. 5,219,788, discloses a chlorine containing plasma etch method for forming from a chlorine containing plasma etchable blanket aluminum containing conductor layer within an integrated circuit microelectronics fabrication a chlorine containing plasma etched patterned aluminum containing conductor layer within the microelectronics fabrication, while attenuating webbing of lower portions of a patterned photoresist etch mask layer employed when forming the chlorine containing plasma etched patterned aluminum containing conductor layer. The method employs a blanket silicon containing layer, such as a blanket silicon layer, a blanket silicon dioxide layer or a blanket silsesquioxane spin-on-glass (SOG) derived layer, formed interposed between: (1) a blanket metal nitride layer formed as an anti-reflective coating (ARC) layer upon the blanket aluminum containing conductor layer; and (2) a blanket photoresist layer from which is formed the patterned photoresist etch mask layer, where the blanket photoresist layer has incorporated therein a photoinitiator which generates acid groups which in absence of the blanket silicon containing layer would interact with the blanket metal nitride layer and thus promote webbing of the patterned photoresist etch mask layer.
In addition, Kadomura, in U.S. Pat. No. 5,540,812 discloses a plasma etch method for forming a within an integrated circuit microelectronics fabrication from a chlorine containing plasma etchable blanket aluminum containing conductor layer having a blanket barrier layer formed thereunder a chlorine containing plasma etched patterned aluminum containing conductor layer co-extensive with a patterned barrier layer formed thereunder, while attenuating corrosion of the chlorine containing plasma etched patterned aluminum containing conductor layer. The method comprises three aspects, including: (1) the use of a disulfur-difluoride etchant gas when etching the blanket barrier layer to form the patterned barrier layer; (2) the use of a silicon oxide hard mask in conjunction with a disulfar-dichioride etchant gas when etching the chlorine containing plasma etchable blanket aluminum containing conductor layer to form the chlorine containing plasma etched patterned aluminum containing conductor layer; and (3) the use of a neutral argon beam processing of the silicon oxide hard mask to form a reduction resistant silicon oxide hard mask layer. The reduction resistant silicon oxide hard mask may be employed with an attenuated thickness in comparison with a non-reduction resistant silicon oxide hard mask layer in the presence of reducing agents, such as boron trichloride, which are typically employed within chlorine containing plasma etchant gas compositions when forming chlorine containing plasma etched patterned aluminum containing conductor layers.
Further, Lianjun et al., in U.S. Pat. No. 5,582,679, discloses a chlorine containing plasma etch method for forming within an integrated circuit microelectronics fabrication from a chlorine containing plasma etchable blanket aluminum containing conductor layer a chlorine containing plasma etched patterned aluminum containing conductor layer with an attenuated taper and an attenuated undercutting. The method employs a chlorine containing plasma etchant gas composition comprising boron trichloride, chlorine and nitrogen, where the nitrogen component is believed to lead to a sidewall polymer formed upon the chlorine containing plasma etched patterned aluminum containing conductor layer, thus providing the attenuated taper and the attenuated undercutting of the chlorine containing plasma etched patterned aluminum containing conductor layer.
Finally, Shen et al., in U.S. Pat. No. 5,665,641, discloses a chlorine containing plasma etch method employing a hard mask layer for forming within an integrated circuit microelectronics fabrication from a chlorine containing plasma etchable blanket aluminum containing conductor layer a chlorine containing plasma etched patterned aluminum containing conductor layer with attenuated stress related defects. Within the method, the hard mask layer is formed at a temperature within a range of about 100 degrees centigrade below a sputtering temperature employed for forming the chlorine containing plasma etchable blanket aluminum containing conductor layer.
The teachings of each of the foregoing references are incorporated herein fully by reference.
Desirable in the art of microelectronics fabrication are additional chlorine containing plasma etch methods which may be employed for forming from chlorine containing plasma etchable blanket layers within microelectronics fabrications chlorine containing plasma etched patterned layers of uniform and attenuated linewidth while employing patterned photoresist etch mask layers of attenuated linewidth and attenuated thickness. It is towards that object that the present invention is directed.